1 // Copyright 2012 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "src/v8.h" 6 7 #if V8_TARGET_ARCH_X64 8 9 #include "src/assembler.h" 10 #include "src/codegen.h" 11 #include "src/debug.h" 12 13 14 namespace v8 { 15 namespace internal { 16 17 bool BreakLocationIterator::IsDebugBreakAtReturn() { 18 return Debug::IsDebugBreakAtReturn(rinfo()); 19 } 20 21 22 // Patch the JS frame exit code with a debug break call. See 23 // CodeGenerator::VisitReturnStatement and VirtualFrame::Exit in codegen-x64.cc 24 // for the precise return instructions sequence. 25 void BreakLocationIterator::SetDebugBreakAtReturn() { 26 ASSERT(Assembler::kJSReturnSequenceLength >= Assembler::kCallSequenceLength); 27 rinfo()->PatchCodeWithCall( 28 debug_info_->GetIsolate()->builtins()->Return_DebugBreak()->entry(), 29 Assembler::kJSReturnSequenceLength - Assembler::kCallSequenceLength); 30 } 31 32 33 // Restore the JS frame exit code. 34 void BreakLocationIterator::ClearDebugBreakAtReturn() { 35 rinfo()->PatchCode(original_rinfo()->pc(), 36 Assembler::kJSReturnSequenceLength); 37 } 38 39 40 // A debug break in the frame exit code is identified by the JS frame exit code 41 // having been patched with a call instruction. 42 bool Debug::IsDebugBreakAtReturn(v8::internal::RelocInfo* rinfo) { 43 ASSERT(RelocInfo::IsJSReturn(rinfo->rmode())); 44 return rinfo->IsPatchedReturnSequence(); 45 } 46 47 48 bool BreakLocationIterator::IsDebugBreakAtSlot() { 49 ASSERT(IsDebugBreakSlot()); 50 // Check whether the debug break slot instructions have been patched. 51 return rinfo()->IsPatchedDebugBreakSlotSequence(); 52 } 53 54 55 void BreakLocationIterator::SetDebugBreakAtSlot() { 56 ASSERT(IsDebugBreakSlot()); 57 rinfo()->PatchCodeWithCall( 58 debug_info_->GetIsolate()->builtins()->Slot_DebugBreak()->entry(), 59 Assembler::kDebugBreakSlotLength - Assembler::kCallSequenceLength); 60 } 61 62 63 void BreakLocationIterator::ClearDebugBreakAtSlot() { 64 ASSERT(IsDebugBreakSlot()); 65 rinfo()->PatchCode(original_rinfo()->pc(), Assembler::kDebugBreakSlotLength); 66 } 67 68 69 #define __ ACCESS_MASM(masm) 70 71 72 static void Generate_DebugBreakCallHelper(MacroAssembler* masm, 73 RegList object_regs, 74 RegList non_object_regs, 75 bool convert_call_to_jmp) { 76 // Enter an internal frame. 77 { 78 FrameScope scope(masm, StackFrame::INTERNAL); 79 80 // Load padding words on stack. 81 for (int i = 0; i < LiveEdit::kFramePaddingInitialSize; i++) { 82 __ Push(Smi::FromInt(LiveEdit::kFramePaddingValue)); 83 } 84 __ Push(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)); 85 86 // Store the registers containing live values on the expression stack to 87 // make sure that these are correctly updated during GC. Non object values 88 // are stored as as two smis causing it to be untouched by GC. 89 ASSERT((object_regs & ~kJSCallerSaved) == 0); 90 ASSERT((non_object_regs & ~kJSCallerSaved) == 0); 91 ASSERT((object_regs & non_object_regs) == 0); 92 for (int i = 0; i < kNumJSCallerSaved; i++) { 93 int r = JSCallerSavedCode(i); 94 Register reg = { r }; 95 ASSERT(!reg.is(kScratchRegister)); 96 if ((object_regs & (1 << r)) != 0) { 97 __ Push(reg); 98 } 99 if ((non_object_regs & (1 << r)) != 0) { 100 __ PushRegisterAsTwoSmis(reg); 101 } 102 } 103 104 #ifdef DEBUG 105 __ RecordComment("// Calling from debug break to runtime - come in - over"); 106 #endif 107 __ Set(rax, 0); // No arguments (argc == 0). 108 __ Move(rbx, ExternalReference::debug_break(masm->isolate())); 109 110 CEntryStub ceb(masm->isolate(), 1); 111 __ CallStub(&ceb); 112 113 // Restore the register values from the expression stack. 114 for (int i = kNumJSCallerSaved - 1; i >= 0; i--) { 115 int r = JSCallerSavedCode(i); 116 Register reg = { r }; 117 if (FLAG_debug_code) { 118 __ Set(reg, kDebugZapValue); 119 } 120 if ((object_regs & (1 << r)) != 0) { 121 __ Pop(reg); 122 } 123 // Reconstruct the 64-bit value from two smis. 124 if ((non_object_regs & (1 << r)) != 0) { 125 __ PopRegisterAsTwoSmis(reg); 126 } 127 } 128 129 // Read current padding counter and skip corresponding number of words. 130 __ Pop(kScratchRegister); 131 __ SmiToInteger32(kScratchRegister, kScratchRegister); 132 __ leap(rsp, Operand(rsp, kScratchRegister, times_pointer_size, 0)); 133 134 // Get rid of the internal frame. 135 } 136 137 // If this call did not replace a call but patched other code then there will 138 // be an unwanted return address left on the stack. Here we get rid of that. 139 if (convert_call_to_jmp) { 140 __ addp(rsp, Immediate(kPCOnStackSize)); 141 } 142 143 // Now that the break point has been handled, resume normal execution by 144 // jumping to the target address intended by the caller and that was 145 // overwritten by the address of DebugBreakXXX. 146 ExternalReference after_break_target = 147 ExternalReference::debug_after_break_target_address(masm->isolate()); 148 __ Move(kScratchRegister, after_break_target); 149 __ Jump(Operand(kScratchRegister, 0)); 150 } 151 152 153 void DebugCodegen::GenerateCallICStubDebugBreak(MacroAssembler* masm) { 154 // Register state for CallICStub 155 // ----------- S t a t e ------------- 156 // -- rdx : type feedback slot (smi) 157 // -- rdi : function 158 // ----------------------------------- 159 Generate_DebugBreakCallHelper(masm, rdx.bit() | rdi.bit(), 0, false); 160 } 161 162 163 void DebugCodegen::GenerateLoadICDebugBreak(MacroAssembler* masm) { 164 // Register state for IC load call (from ic-x64.cc). 165 // ----------- S t a t e ------------- 166 // -- rax : receiver 167 // -- rcx : name 168 // ----------------------------------- 169 Generate_DebugBreakCallHelper(masm, rax.bit() | rcx.bit(), 0, false); 170 } 171 172 173 void DebugCodegen::GenerateStoreICDebugBreak(MacroAssembler* masm) { 174 // Register state for IC store call (from ic-x64.cc). 175 // ----------- S t a t e ------------- 176 // -- rax : value 177 // -- rcx : name 178 // -- rdx : receiver 179 // ----------------------------------- 180 Generate_DebugBreakCallHelper( 181 masm, rax.bit() | rcx.bit() | rdx.bit(), 0, false); 182 } 183 184 185 void DebugCodegen::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) { 186 // Register state for keyed IC load call (from ic-x64.cc). 187 // ----------- S t a t e ------------- 188 // -- rax : key 189 // -- rdx : receiver 190 // ----------------------------------- 191 Generate_DebugBreakCallHelper(masm, rax.bit() | rdx.bit(), 0, false); 192 } 193 194 195 void DebugCodegen::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) { 196 // Register state for keyed IC load call (from ic-x64.cc). 197 // ----------- S t a t e ------------- 198 // -- rax : value 199 // -- rcx : key 200 // -- rdx : receiver 201 // ----------------------------------- 202 Generate_DebugBreakCallHelper( 203 masm, rax.bit() | rcx.bit() | rdx.bit(), 0, false); 204 } 205 206 207 void DebugCodegen::GenerateCompareNilICDebugBreak(MacroAssembler* masm) { 208 // Register state for CompareNil IC 209 // ----------- S t a t e ------------- 210 // -- rax : value 211 // ----------------------------------- 212 Generate_DebugBreakCallHelper(masm, rax.bit(), 0, false); 213 } 214 215 216 void DebugCodegen::GenerateReturnDebugBreak(MacroAssembler* masm) { 217 // Register state just before return from JS function (from codegen-x64.cc). 218 // ----------- S t a t e ------------- 219 // -- rax: return value 220 // ----------------------------------- 221 Generate_DebugBreakCallHelper(masm, rax.bit(), 0, true); 222 } 223 224 225 void DebugCodegen::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) { 226 // Register state for CallFunctionStub (from code-stubs-x64.cc). 227 // ----------- S t a t e ------------- 228 // -- rdi : function 229 // ----------------------------------- 230 Generate_DebugBreakCallHelper(masm, rdi.bit(), 0, false); 231 } 232 233 234 void DebugCodegen::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) { 235 // Register state for CallConstructStub (from code-stubs-x64.cc). 236 // rax is the actual number of arguments not encoded as a smi, see comment 237 // above IC call. 238 // ----------- S t a t e ------------- 239 // -- rax: number of arguments 240 // ----------------------------------- 241 // The number of arguments in rax is not smi encoded. 242 Generate_DebugBreakCallHelper(masm, rdi.bit(), rax.bit(), false); 243 } 244 245 246 void DebugCodegen::GenerateCallConstructStubRecordDebugBreak( 247 MacroAssembler* masm) { 248 // Register state for CallConstructStub (from code-stubs-x64.cc). 249 // rax is the actual number of arguments not encoded as a smi, see comment 250 // above IC call. 251 // ----------- S t a t e ------------- 252 // -- rax: number of arguments 253 // -- rbx: feedback array 254 // -- rdx: feedback slot (smi) 255 // ----------------------------------- 256 // The number of arguments in rax is not smi encoded. 257 Generate_DebugBreakCallHelper(masm, rbx.bit() | rdx.bit() | rdi.bit(), 258 rax.bit(), false); 259 } 260 261 262 void DebugCodegen::GenerateSlot(MacroAssembler* masm) { 263 // Generate enough nop's to make space for a call instruction. 264 Label check_codesize; 265 __ bind(&check_codesize); 266 __ RecordDebugBreakSlot(); 267 __ Nop(Assembler::kDebugBreakSlotLength); 268 ASSERT_EQ(Assembler::kDebugBreakSlotLength, 269 masm->SizeOfCodeGeneratedSince(&check_codesize)); 270 } 271 272 273 void DebugCodegen::GenerateSlotDebugBreak(MacroAssembler* masm) { 274 // In the places where a debug break slot is inserted no registers can contain 275 // object pointers. 276 Generate_DebugBreakCallHelper(masm, 0, 0, true); 277 } 278 279 280 void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) { 281 masm->ret(0); 282 } 283 284 285 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) { 286 ExternalReference restarter_frame_function_slot = 287 ExternalReference::debug_restarter_frame_function_pointer_address( 288 masm->isolate()); 289 __ Move(rax, restarter_frame_function_slot); 290 __ movp(Operand(rax, 0), Immediate(0)); 291 292 // We do not know our frame height, but set rsp based on rbp. 293 __ leap(rsp, Operand(rbp, -1 * kPointerSize)); 294 295 __ Pop(rdi); // Function. 296 __ popq(rbp); 297 298 // Load context from the function. 299 __ movp(rsi, FieldOperand(rdi, JSFunction::kContextOffset)); 300 301 // Get function code. 302 __ movp(rdx, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset)); 303 __ movp(rdx, FieldOperand(rdx, SharedFunctionInfo::kCodeOffset)); 304 __ leap(rdx, FieldOperand(rdx, Code::kHeaderSize)); 305 306 // Re-run JSFunction, rdi is function, rsi is context. 307 __ jmp(rdx); 308 } 309 310 const bool LiveEdit::kFrameDropperSupported = true; 311 312 #undef __ 313 314 } } // namespace v8::internal 315 316 #endif // V8_TARGET_ARCH_X64 317